Method and system of control signaling for a wireless access network

ABSTRACT

A method and system of control signaling for a wireless access network includes receiving from a wireless access network a signaling message for a mobile device. The signaling message is in a wireless-specific format. The signaling message is converted to a native format of a call agent to generate a call agent message. The call agent message comprises wireless-specific information of the signaling message.

RELATED PATENT APPLICATIONS

This application is related to U.S. patent application Ser. No.09/907,785 entitled “Method and System for Providing SupplementaryServices for a Wireless Access Network,” and U.S. patent applicationSer. No. 09/908,081 entitled “Method and System for ProvidingWireless-Specific Services for a Wireless Access Network,” all filed onJul. 18, 2001.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the field of wirelesscommunications, and more particularly to a method and system of controlsignaling for a wireless access network.

BACKGROUND OF THE INVENTION

Traditional wireless networks include a number of base transceiverstations (BTSs) and one or more mobile switching centers (MSCs) and basestation controllers (BSCs). The BTSs each cover a geographic region, orcell of the wireless network and communicate with mobile telephones inthe cell. The MSCs/BSCs provide switch and soft handoff functionalityfor the wireless network.

To support mobility and supplementary services within and acrosswireless access networks, wireless-specific interfaces such as IS-41 areused to communicate with a network control plane. Integration of suchwireless specific interfaces into call agents or servers of the controlplane for signaling between the control plane and the access network isproblematic because the call agent/servers typically utilize sessioninitiation protocol (SIP) for signaling and standardized SIP does notsupport wireless-specific functionality.

SUMMARY OF THE INVENTION

The present invention provides a method and system of control signalingfor a wireless access network that substantially eliminates or reducesthe problems and disadvantages associated with previous methods andsystems. In a particular embodiment, session initiation protocol (SIP)extensions are used to support wireless-specific functionality and tointegrate or interface mobility control functions (MCF) to a call agentor call server.

In accordance with one embodiment of the present invention, a method andsystem of control signaling for a wireless access network includesreceiving from the wireless access network a signaling message in awireless-specific format. The signaling message may be for a mobiledevice within, entering, leaving or otherwise associated with thewireless access network. The signaling message is converted to a nativeformat of a call agent to generate a call agent message for processingby the call agent. The call agent message includes wireless-specificinformation of the signaling message.

More specifically, in accordance with a particular embodiment of thepresent invention, the call agent message is a SIP message. In thisembodiment, the SIP message may include an extension carrying thewireless-specific information. The signaling message may be a callestablishment, mobility management, registration, location update orother suitable message for providing wireless-specific functionality tothe mobile device.

Technical advantages of the present invention include providing animproved method and system of control signaling for a wireless accessnetwork. In particular, wireless-specific messages are converted to anative format for processing by a common or shared call agent.Accordingly, the call agent need not be reprogrammed to communicate witha mobility manager of a wireless access network over a wireless-specificinterface.

Another technical advantage of the present invention includes providingan improved mobility manager, or mobility control function (MCF) for thecontrol plane of the communication network. In particular, the MCF isintegrated or interfaced with a call agent or call server to provide acommon control network across wireless and wireline networks. The MCFmay use an extended (SIP) interface to communicate with the call agentand translate between the wireless-specific interface and the extendedSIP interface. Because SIP is a widely-used protocol, wireless-specificextensions can be standardized across networks for enhancedinteroperability.

Still another technical advantage of the present invention includessupporting new location-based or other wireless-specific services withthe call agent. For example, using extended SIP, the call agent maysupport call establishment, mobility management, registration andlocation updates for mobile devices in a wireless access network.Location-based services may provide the location of a mobile user to acalled party, a calling party or business or other establishment in thearea of the mobile user.

The various embodiments of the present invention may include all, someor none of the enumerated advantages. Furthermore, other advantages ofthe present invention will be readily apparent to one skilled in the artfrom the following figures, descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsadvantages, reference is now made to the following description, taken inconjunction with the accompanying drawings, wherein like numeralsrepresent like parts, in which:

FIG. 1 is a block diagram illustrating an integrated wireline andwireless communication network in accordance with one embodiment of thepresent invention;

FIG. 2 is a flow diagram illustrating a method for wireless-specificcontrol signaling in the communication network of FIG. 1 in accordancewith one embodiment of the present invention;

FIG. 3 is a flow diagram illustrating a method for mobile deviceregistration in the communication network of FIG. 1 in accordance withone embodiment of the present invention;

FIG. 4 is a table illustrating session initiation protocol (SIP)messages for basic services and mobility management for mobile devicesin the communication network of FIG. 1 in accordance with one embodimentof the present invention;

FIG. 5 is a flow diagram illustrating a method for basic call handlingfor mobile devices in the communication network of FIG. 1 in accordancewith one embodiment of the present invention;

FIG. 6 is a table illustrating SIP messages for basic call handling formobile devices in the communication network of FIG. 1 in accordance withone embodiment of the present invention;

FIGS. 7A–B are flow diagrams illustrating methods for handoffs betweenlegacy systems and patent networks for mobile devices in thecommunication network of FIG. 1 in accordance with one embodiment of thepresent invention;

FIGS. 8A–B are tables illustrating SIP messages for handoffs between thelegacy systems and packet networks for mobile devices in thecommunication network of FIG. 1 in accordance with one embodiment of thepresent invention;

FIGS. 9A–B are block diagrams illustrating connections for mobile devicehandoff in the packet network and legacy system of FIG. 1 in accordancewith one embodiment of the present invention;

FIG. 10 is a flow diagram illustrating a method for providingsupplementary services for wireless calls in the communication networkof FIG. 1 in accordance with one embodiment of the present invention;

FIGS. 11A–I are tables illustrating SIP messages for providingsupplementary services for wireless calls in the communication networkof FIG. 1 in accordance with one embodiment of the present invention;and

FIG. 12 is a call flow diagram illustrating messages for caller locationpresentation and restriction services in accordance with one embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a communication network 10 in accordance with oneembodiment of the present invention. In this embodiment, thecommunication network 10 includes a cellular wireless network in whichterrestrial wireless transmissions originate in geographically delimitedcells. It will be understood that the present invention may be used inconnection with satellite and other suitable wireless networks.

Referring to FIG. 1, the communication network 10 includes a wirelessnetwork 12 connected to a wireline network 14 through an air gateway 16that separates signaling and bearer traffic and converts traffic betweenwireless and wireline formats. The air gateway may comprise a packetdata serving node (PDSN) for CDMA or CDMA 2000 or comprise a signalinggateway server node (SGSN) for universal mobile telecommunicationssystem (UMTS) or other suitable node. In the CDMA embodiment, the PDSN16 may have a router that directs traffic in the bearer plane betweenthe wireless and wireline networks 12 and 14. In one embodiment, thePDSN 16 includes a data interworking function (IWF) that providesconnectivity between the wireless and the wireline networks 12 and 14via circuit switched and packet switched wireless data protocols. Itwill be understood that connectivity between the wireless and wirelinenetworks 12 and 14 may be otherwise suitably provided without departingfrom the scope of the present invention.

The wireless and wireline networks 12 and 14 are managed by aservice/control layer 20. In one embodiment, the wireless network 12comprises a radio access network (RAN), the wireline network 14comprises an Internet protocol (IP) core network 14 and theservice/control layer 20 comprises a core control network 20. In thisembodiment, the RAN 12 is coupled to the core control network 20 througha mobility control function (MSF), air agent or other suitable mobilitymanager 22. The IP core network 14 is coupled to the core controlnetwork 20 through the MCF 22 and a call agent 24. The MCF 22 may, inone embodiment, be integrated into the call agent 24.

As described in more detail below, the call agent 24 provides for homebase control of basic call and feature interaction. The call agent 24 isalso responsible for handling call roaming between different networkswhile wireless mobility during a call is handled by the MCF 22. In oneembodiment, the MCF 22 provides the call agent 24 with handoff addressesand the call agent 24 communicates with the IP core network 14 to changecall circuits for handoffs. The MCF 22, call agent 24 and other elementof the communication network 10 may perform a task by themselves takinga specified action, initiating the action and/or directing anotherelement to take the action.

The MCF 22 and the call agent 24 communicate signaling messages over anextended session initiated protocol (SIP) or other native interface, orformat of the call agent 24. Accordingly, the call agent 24 may handlewireless-specific events of the RAN 12 without wireless-specificinterfaces to the MCF 22. The native interface of the call agent 24 maycomprise any suitable interface utilized by the call agent 24 forprocessing control, management or other signaling messages for one ormore of an IP, DSL and/or other wireline network 14. In one embodiment,the native interface of the call agent 24 is a common interface used bythe call agent 24 to process signaling messages for substantially all orall connected wireline, wireless and other networks.

The RAN 12 includes a number of base transceiver stations (BTSs) 30connected to base station controllers (BCSs) 32 over a RAN transportring or network 34. The BTSs 30 each cover a geographic region, or cellof the RAN 12 and communicate with mobile devices 36 in the cell. Asused herein, each means every one of at least a subset of the identifieditems. The mobile devices 36 may be cell phones, data phones, portabledata devices, portable computers, hand-held devices, hand sets, portablenetwork appliances or other suitable devices or stations capable ofcommunicating information over a wireless link 38.

The BSCs 32 are connected to each other, to the PDSN 16 and to the MCF22 of the core control network 20. The BSCs 32 and the MCF 22 provideswitch and soft handoff functionality for the RAN 12. In this way,voice, video, data and other information is routed to and from themobile devices 36 and connections are maintained with the mobile devices36 as they move throughout the RAN 12 and between the RAN 12 and otherlegacy systems and/or packet networks.

The wireless link 38 is a radio frequency (RF) link. The wireless link38 may be based on established technologies or standards such as IS-54(TDMA), IS-95 (CDMA), GSM and AMTS, 802.11 base LAN, or more recenttechnology such as CDMA 2000 and W-CDMA or proprietary radio interfaces.In a particular embodiment, wireless link 38 comprises a code divisionmultiple access (CDMA) link based on a CDMA standard and in whichpackets are segmented into radio frames for transmission over thewireless interface and reassembled by the receiving device toreconstitute the packets.

The IP core network 14 includes a packet-switched or other suitable coretransport network 50 connecting a number of routers, servers and/orgateways to each other, to the PDSN 16 and thus the RAN 12 as well asthe core control network 20. In a particular embodiment, the coretransport network 50 connects the PDSN 16, and thus the RAN 12 to thepublic switch telephone network (PSTN) through a voice/PSTN gateway 52.The core transport network 50 may also connect the PDSN 16 and RAN 12 toa remotely located PDSN through a PDSN/foreign agent (FA) gateway 54, toglobal system for mobile communications (GSN) through GSN gateway 56 andto a handoff gateway 58. The PDSN/FA gateway 54 provides a data gatewayfor CDMA 2000. The GSN gateway 56 provides a data gateway. The handoffgateway 58 provides a gateway for voice traffic. It will be understoodthat the core transport network 50 may connect the PDSN 16 and RAN 12 toother suitable gateways, such as a wireless access protocol (WAP)gateway for a home agent corporate virtual private network (VPN). Thegateways 52, 54, 56 and 58 along with a control plane signaling system 7(SS7) gateway 60 are managed by the call agent 24 of the core controlnetwork 20.

The handoff gateway 58 interfaces to the legacy MSC/BSC network. In aparticular embodiment, DS0/DS1 circuits are used for interfacing thelegacy networks and the circuits are added and deleted during handofffrom packet network to legacy system. In operation, the handoff gateway58 provides a point of attachment for calls across networks. A call maybe any suitable connection or set of connections in which video, audio,voice, data or other information is exchanged. It will be understoodthat functionality of the handoff gateway 58 may be implemented in thevoice/PSTN gateway 52 or otherwise suitably implemented.

The core control network 20 includes the MCF 22 and the call agent 24,as well as an air broker 80, lightweight director access protocols(LDAP) 82, legacy MSC 84, home location register (HLR)/visitor locationregister (VLR) or other suitable registration database 86 and serviceagent/feature server (FS) 88. In a particular embodiment, the MCF 22 maycommunicate with the RAN 12 and the legacy MSC using IS-41 or otherwireless-specific interface. A wireless-specific interface is aninterface or protocol especially adapted for radio frequency or mobiletraffic or signaling and not typically used by wireline networks 14. ThePDSN 16 may communicate with the MCF 22 using media gateway controlprotocol (MGCP)/common open policy server (COPS). The MCF 22 maycommunicate with the FS 88 using markup language (XML). The call agentmay communicate with the FS 88 using SIP and may communicate with theHLR/VLR 86 and the legacy MSC using IS-41-D. It will be understood thatthe RAN 12, IP core network 14 and core control network 20 maycommunicate internally and with each other using other suitableinterfaces, protocols and formats. It will be further understood thatcall agent 24, MCF 22 as well as other elements in the core controlnetwork 20 and/or radio access and IP core networks 12 and 14 mayotherwise communicate with each other. For example, the call agent 24may directly communicate with and control the air gateway and/or PDSN16. Similarly, the MCF 22 may directly communicate and/or interface withthe HLR/VLR 86.

The MCF 22 provides a wireless access interface for the RAN 12 andsupport wireless-specific and mobility functions of the RAN 12. In aparticular embodiment, the MCF 22 provides temporary line directorynumber (TLDN) management and innerworks with the call agent 24 to assignTLDN for incoming mobile calls. The MCF 22 may manage all types ofhandoffs and may interface with the handoff gateway 58 for inner systemhandoffs. The MCF 22 may also support a vocoder and may anchor thebearer traffic path at the PDSN 16, except in cases where the mobilesubscriber is roaming off net. A mobile subscriber is roaming off netwhen it is roaming and registered in another packet network or a legacysystem. A packet network is a network where the data and control planeare IP based or packet switched. The legacy system comprises BTSs, BSCs.and MSCs. A mobile subscriber is roaming on net when it is registeredand active in the packet network managed by the MCF 22.

The call agent 24 may be a generic and/or shared call agent operable tomanage call establishment for a plurality of network types, such as DSL,cable and wireless. The generic call agent 24 need not havewireless-specific interfaces to communicate with the RAN 12. In oneembodiment, the call agent 24 provides call control and supplementaryservices using internal or external FS 88. The call agent 24 may alsoprovide management and mobility support in connection with the MCF 22and provide a call signaling anchor. Additionally, the call agent 24 mayprovide other services such as message waiting notification, messageretrieval, short message service and the like. The call agent 24interfaces with the legacy MSC 84 as well as PSTN via the PSTN gateway52. The call agent 24 may have an ISDN user port (ISUP)/SS7 signalinterface to the gateways 52, 54, 56 and 58.

Other functions of the call agent 24 may include feature code update andacknowledgment provided to mobile devices 36 that are on net, callretrieval to access voice mail service, call terminations to mobilesubscribers homed in the legacy MSC 84. For retrieved calls, the callagent 24 may provide a retrieve trigger point or detect during digitanalysis. For outgoing call originations from the packet network toother mobile subscribers, the call agent 24 may determine after a digitanalysis that the number called is another mobile subscriber by using ablock of mobile subscribers registered on the network that can bequeried to determine if the number is a mobile subscriber or a PSTNcall. The call agent 24 may additionally innerwork with the MCF 22 whena TLDN is assigned for call terminations to on net mobile subscribers inthe packet network. The call agent 24 may further notify the MCF 22 whena TLDN expires to allow the MCF 22 to free up the TLDN.

To support wireless-specific functionality, the MCF 22 and call agent 24communicate using extended SIP or other suitable protocol native to thecall agent 24. In a particular embodiment, the MCF 22 may comprise an Ainterface input port for communicating with the RAN 12, A translator fortranslating A interface formatted messages to extended SIP formattedmessages and an extended SIP interface for communicating with the callagent 24. In this embodiment, the call agent 24 may include an extendedSIP interface for communicating with the MCF 22 and an IS-41-D interfacefor communicating with the legacy network 84 and HLR/VLR 86. It will beunderstood that the MCF 22 and call agent 24 may comprise other suitablefunctionality without departing from the scope of the present invention.

In the SIP embodiment, core SIP defined by RFC 2543 is used for basiccall setup. SIP extensions are used to carry wireless-specificparameters and also used support the transport of mid-call and callindependent signaling as well as to register or de-register newsubscribers. The SIP extensions may be negotiated during call set up. Ina particular embodiment the multipart multipurpose Internet mailextension (MIME) with multipart/mixed media type is used to allow theSIP body to contain multiple payloads. The single-part MIME is also usedwhen only one MCAP payload is needed in the SIP message. The MCAPpayload is case intensive, text-based data in an event name followed byparameters format. The format and number of mandatory parameters dependon the event name. The SIP:INFO method with MCAP payload is used tosupport mid-call signaling and call independent signaling. Standard SIPregister requests are extended to carry the MCAP payload containingextended register parameters to support mobile registration.

The interface for the SIP extensions may comprise a SIP request orresponse identifier, followed by SIP headers/parameters, followed bycontent-type: application/application type, followed bycontent-length:xx, followed by carriage return line feed (CRLF) followedby the message body with the requested event or notification. Events andnotifications may be optional and only used if the SIP request orresponse has not itself determined the event that occurred.

The MCF 22, call agent 24, and other nodes and/or elements of the corecontrol network 20, RAN 12 and IP core network 14 may be implemented asfunctional instructions, code or other logic encoded in media. The logicencoded in media may comprise software stored on a computer-readablemedium as well as programmed application-specific integrated circuit(ASIC), field programmable gate array (FPGA) or other programmedhardware. The media may comprise different mediums and may bedistributed across a plurality of platforms.

FIG. 2 is a flow diagram illustrating a method for wireless-specificcontrol signaling in a communication network 10 in accordance with oneembodiment of the present invention. In this embodiment, controlsignaling is received in the core control network by the MCF 22,converted to extended SIP and forwarded to the common, or generic callagent 24 for processing. Thus, the MCF may be a SIP client and/or SIPproxy. It will be understood that if the control signaling is receivedin an extended SIP format, it need not be translated by the MCF 22 butmay be passed directly to the call agent 24 for processing.

Referring to FIG. 2, the method begins at step 100 in which the mobiledevice 36 generates a signaling message for a wireless event in the Ainterface, IS-41, IS-634 for CDMA, RAN application port (RANAP (UMTS))or other wireless-specific format. Next, at step 102, the mobile device36 forwards the signaling message to the MCF 22 through the RANtransport network 34 and the BSC 32. In the IS-41 embodiment, thesignaling message may be received at an IS-41 port of the MCF 22.

Proceeding to step 104, the MCF 22 converts the signaling message fromthe wireless-specific format to a call agent message in the SIP format.The MCF 22 may convert the message by translating the message or byotherwise suitably generating a new message based on the signalingmessage. The conversion may comprise interworking or tunneling forcarrying the wireless-specific information into the SIP domain. Fortunneling, session description protocol (SDP) may be enhanced andutilized. The SIP message may incorporate location or other wirelessevent information from the message or information indicative of thatinformation in the signaling message. In a particular embodiment, thesignaling message may be mapped to a SIP message using a lookup table.The SIP message may be a standardized SIP message or include extensions.For extensions, wireless event information may be extracted from thesignaling message during conversion and encapsulated into an extensionin the body of a SIP message.

At step 106, the call agent or SIP message, with or without anextension, is forwarded to the call agent 24 for handling. Accordingly,the call agent 24 need not communicate with the MCF 22 using a accessnetwork-specific protocol. The call agent 24 may respond to the SIPmessage and/or generate further control messages to process the SIPmessage.

FIG. 3 illustrates a method for mobile device registration in accordancewith one embodiment of the present invention. Referring to FIG. 3, themethod begins at step 120 in which a mobile registration message isreceived by the call agent 24 from the MCF 22. As previously described,the mobile registration message as well as other messages received bythe call agent 24 from the MCF 22 are translated or otherwise convertedby the MCF 22 into extended SIP and received by the call agent 24 at anextended SIP interface operable to receive and process standard andextended SIP. At step 122, the mobile device 36 is registered by thecall agent 24 in connection with the HLR/VLR 86. Alternatively, the MCF22 may pass the message to the HLR/VLR 86 through an IS-41 interface.

Step 122 leads to state 124 in which the mobile is registered in the RAN12. In response to an unregister message, state 124 transitions to step126 in which the mobile device 36 is unregistered by the call agent 24.Returning to state 124, in response to a cancellation message from themobile device 36, state 124 transitions again to step 126 in which themobile device 36 is unregistered. Also at state 124, in response to theexpiration of a timer or predefined period of time, state 124transitions to decisional step 128.

At decisional step 128, if a location update is not received within thepredefined period of time, the No branch also leads to step 126 in whichthe mobile device 36 is unregistered by the call agent 24. If a locationupdate is received within the predefined period of time, the Yes branchof decisional step 128 returns to registered state 124. Thus, absent anunregistration or cancellation message and while location updates arereceived, mobile device 36 will remain in the registration state 124.When the mobile device 36 unregisters, cancels registration or fails toupdate its location, as previously described, the mobile device 36 isunregistered.

FIG. 4 illustrates signaling messages for basic call services andmobility management for mobile devices 36 in the RAN 12 in accordancewith one embodiment of the present invention. In this embodiment, theRAN 12 communicates with the call agent 24 through the MCF 22 usingextended SIP, which is a SIP format or set of messages including one ormore SIP extensions.

Referring to FIG. 4, the SIP messages for basic services of mobilitymanagement include a mobile registration message 140, a mobileunregisters message 142, a location update request (LUR) message 144 anda registration cancellation message 146. It will be understood thatother suitable messages may be used for basic services of mobilitymanagement for a wireless access network without departing from thescope of the present invention.

The mobile registration message 140 is an extended SIP message generatedby the MCF 22 and forwarded to the call agent 24 for processing. Themobile unregisters message 142 and LUR message 144 are also extended SIPmessages generated by the MCF 22 and forwarded for processing by thecall agent 24. The registration cancellation message is an extended SIPmessage generated by the call agent 24 based on a HLR/VLR 86 message forforwarding to the MCF 22 for processing. The SIP extension parametersfor basic services and mobility management include the number of themobile, or ESN, and cell I.D. It will be understood that other suitableextensions may be included with the extended SIP messages withoutdeparting from the scope of the present invention.

FIG. 5 illustrates a method for basic call handling for the RAN 12 inaccordance with one embodiment of the present invention. In thisembodiment, call handling messages are converted by the MCF 22 toextended SIP and forwarded to the call agent 24 for processing.

Referring to FIG. 5, the method begins at step 160 in which a callorigination message is received by the MCF 22 for the mobile device 36.A message is generated for the mobile device 36 when it is generated bythe mobile device, for delivery to the mobile device or in connectionwith a call or event associated with the mobile device. At step 162, thecall origination message is forwarded to call agent 24 after translationor other suitable conversion by the MCF 22 to extended SIP format.

Proceeding to decisional step 164, the call agent 24 determines whetherthe mobile device 36 is on net by accessing the HLR/VLR 86. If themobile device 36 is on net, the Yes branch of decisional step 164 leadsto step 166. At step 166, profile information for the mobile device 36is retrieved at the call agent 24 from the FS 88 and/or HLR/VLR 86.Next, at step 168, the call is routed from the call agent 24 to themobile device 36 through the MCF 22. Step 168 leads to the end of theprocess by which mobile device 36 in the RAN 12 is connected to anincoming call.

Returning to decisional step 164, if the mobile device 36 is not on net,the No branch of decisional step 164 leads to step 170. At step 170, thecall agent 24 requests the location of the mobile device 36 from theHLR/VLR 86. Next, at step 172, HLR/VLR 86 requests TLDN from the servingMSC/packet network.

Proceeding to decisional step 174, if the mobile device 36 is notactive, the No branch leads to step 176 in which the call agent 24routes the call to a voicemail server. In one embodiment, the responsefrom the HLR/VLR 86 will include the destination of the voicemail serverif the mobile station is not active.

If the mobile station is active, the Yes branch of decisional step 174leads to step 178 in which the HLR/VLR 86 receives the TLDN from theserving MSC/packet network. At step 180, the TLDN is forwarded to thecall agent 24. At step 182, the call agent 24 redirects the call basedon the TLDN to the serving MSC/packet network. Step 182 as well as step176 lead to the end of the process by which an incoming call isconnected to the active mobile device 36 or to a voicemail server if themobile device 36 is not active.

FIG. 6 illustrates messages for basic call handling for the mobiledevice 36 in the RAN 12 in accordance with one embodiment of the presentinvention. In this embodiment, the RAN 12 communicates with the callagent 24 through the MCF 22 using extended SIP.

Referring to FIG. 6, the SIP messages for basic call handling include aroute request message 200, a response to SIP information message 202 anda TLDN timer expiry message 204. It will be understood that othersuitable signaling messages may be used for basic call handling for theRAN 12 or other suitable access network without departing from the scopeof the present invention.

The route request message 200 originates with the HLR 86 and istranslated by the call agent 24 from the IS-41 format to the extendedSIP format and forwarded to the MCF 24 for processing. The response toSIP information message 202 is generated by the MCF 22 in the extendedSIP format and forwarded to the call agent 24 for processing. The TLDNtimer expiry message is also generated by the MCF 22 and forwarded tothe call agent 24 for processing. The TLDN and TLDN timer expirymessages 202 and 204 include TLDN SIP extension parameters.

FIGS. 7A–B illustrate methods for handoff between the packet network andlegacy systems in accordance with one embodiment of the presentinvention. In particular, FIG. 7A illustrates a method for packetnetwork to legacy system handoff in which the caller remains anchored atthe call agent 22 and the bearer path remains anchored to the handoffgateway 58. In addition, the call remains active until facilitiesreleased is received by the MCF 22. In other embodiments, the bearerpath may be anchored in the PSTN gateway 52 or the wireless-specificaccess gateway 16. FIG. 7B illustrates a method for legacy system topacket network handoff. In handoffs between the legacy system and thepacket network, the MCF 22 receives a message indicative of roaming bythe mobile device 36 and processes the handoff in connection with thecall agent 24.

Referring to FIG. 7A, packet network to legacy system handoff begins atstep 220 in which the mobile device 36 roams from the packet network tothe legacy system. Next, at step 222, the MCF 22 messages the legacy MSCto set up an inner system trunk for handoff.

Proceeding to step 242, the legacy MSC 84 initiates handoff. At step226, the legacy MSC 84 completes handoff. The mobile device 36 registerswith the serving MSC at step 228.

Proceeding to decisional step 230, if the packet network is the anchorfor the connection, the Yes branch leads to step 232 in which the callis maintained in the packet network. At step 234, as long as the call isnot terminated but remains active, the No branch returns to step 232 inwhich the call is maintained. When the call is terminated, the Yesbranch of decisional step 234 leads to step 236 in which the MCF 22 isreleased as well as the handoff gateway 58 and the call agent 24 of thepacket network. Returning to decisional step 230, if the packet networkis not the anchor for the connection, the No branch leads to step 236 inwhich the MCF 22 and the call agent 24 are released. Step 236 leads tothe end of the process.

Referring to FIG. 7B, the method for legacy system to packet networkhandoff begins at step 260 in which the mobile device 36 roams from thelegacy system to the packet network. Next, at step 262, the legacysystem messages the MCF 22 to set up an inner system trunk for handoff.

Proceeding to step 264, the MCF 22 requests BCS 32 resources. At step266 the mobile device 36 registers with the MCF 22 and HLR/VLR 86through the call agent 24.

At step 268, the HLR/VLR 86 provides the call agent 24 with profileinformation for the call. At step 270, the MCF 24 releases the legacyMSC 84. Step 270 leads to the end of the legacy system to packet networkhandoff.

Handoff between packet networks are handled by the MCF 22 when betweenRANs 12, by the call agent 24 when between disparate MCFs 22 and betweencall agents 24 for handoff across disparate call agents. In each case,the MCF 22 and call agent 24 are kept informed of the point ofattachment through SIP information messages. SIP messages may also beused for handoff authorization.

FIGS. 8A–B illustrate messages for handoffs between the packet networkand the legacy system in accordance with one embodiment of the presentinvention. In particular, FIG. 8A illustrates packet network to legacysystem handoff messages. FIG. 8B illustrates legacy system to packetnetwork handoff messages.

Referring to FIG. 8A, the packet network to legacy system handoffmessages include handoff required message 280, facilities directiveresponse message 282, mobile on channel message 284, registrationmessage 286 and facilities release message 288. The handoff requiredmessage 280 is communicated between the MCF 22 and the legacy MSC 84.The facilities directive and mobile on channel messages 282 and 284 arecommunicated from the legacy MSC to the MCF 22. The registration message286 is communicated between the call agent 24 and the MCF 22. Thefacilities release message 288 is communicated between the MCF 22 andthe call agent 24.

Referring to FIG. 8B, the legacy system to packet network handoffmessages include a facilities directive request message 290, afacilities directive response message 292 and a handoff complete message294. The facilities directive request message 290 is communicatedbetween the legacy MSC 84 and the MCF 22. The facilities directiveresponse message 292 is communicated from the MCF 22 to the call agent24. The handoff complete message 294 is communicated from the MCF 22 tothe legacy MSC 84. The facilities directive response message 292includes the ESN and cell I.D. SIP extension parameters.

FIGS. 9A–B illustrate connections for mobile device handoff connectionsin the packet network and/or legacy system in accordance with oneembodiment of the present invention. In particular, FIG. 9A illustratesanchoring points for packet network to legacy system handoff. FIG. 9Billustrates anchoring points in a packet network for handoff in thelegacy system.

Referring to FIG. 9A, for a connection between a PSTN-based telephone300 and a mobile device 301 in the packet network 303, signaling traffic304 is routed through the PSTN 302 to a packet core control network 305for processing. Bearer traffic 306 is routed through the PSTN 302 to thecore transport network 307 and to the air gateway 308 for delivery tothe mobile device 301.

In response to roaming of the mobile device 301 from the packet network302 to a legacy system 309, signaling traffic 304 remains anchored atthe MCF of the packet core control network but is forwarded back throughthe call agent of the packet core control network 305 and through thePSTN 302 to a legacy core control network 310 for processing. Signalingbetween the MCF and call agent may be over an extended SIP or othersuitable interface. The bearer traffic 306 remains anchored at the airgateway 308 but is routed back through the core transport network 307 toan MSC and the legacy control network 310 for delivery to the mobiledevice 301.

Referring to FIG. 9B, for a connection between a mobile device 311 in alegacy system 312 and a mobile device 313 in a packet network 314,bearer traffic is forwarded to and from the mobile device 311 through aBTS, BSC and MSC of the legacy network 312 and a handoff gateway 315 ofa core transport network. From the handoff gateway 315, bearer trafficis forwarded to an air gateway and RAN of the packet network 314. Inresponse to the mobile device 311 roaming from a first MSC 316 to asecond MSC 317 in the legacy system 312, a time division multiplexed(TDM) circuit for the connection is switched from a first TDM circuit318 between the first MSC 316 and the air gateway of the packet network314 to a second TDM circuit 319 between the second MSC 317 and the airgateway of the packet network 314. For handoff, the handoff gateway 315may detect mobile roaming and inform a call agent of the packet corecontrol network which in turn may inform an MCF and the MCF inform theair gateway to switch the TDM circuit. Signaling between the MCF andcall agent may be over an extended SIP or other suitable interface.

FIG. 10 illustrates a method for providing supplementary services forwireless calls in accordance with one embodiment of the presentinvention. In this embodiment, supplementary services are provided bythe call agent 24 in connection with the MCF 22 and the PSDN 16.

Referring to FIG. 10, the method begins at step 300 in which a wirelesscall is set up. Next, at step 302, call triggers for the call and thusthe mobile device 36 are retrieved from the FS 88 by the call agent 24.Proceeding to step 304, the wireless-specific triggers are downloaded tothe MCF 22 using extended SIP messages. In one embodiment, the serviceprofile/triggers may be received by the MCF 22 during registration/callorigination. At step 306, selected wireless-specific triggers aredownloaded to the PDSN 16.

Step 306 leads to state 308 in which the PDSN 16 or other node monitorsthe call for events associated with the selected wireless-specifictriggers. In one embodiment, the events may be detected in/at the MCF22, the PDSN or other element of the air gateway 16 and/or other bearergateway. In response to a specified wireless event, state 308transitions to step 310 in which the call agent 24 is notified by theMCF 22 using extended SIP. Next, at step 312, the call agent 24processes the SIP message in connection with the FS 88 to provide thesupplementary service associated with the event.

Step 312 returns to step 308 in which the call is further monitored forthe specified events. Upon call termination, state 308 transitions tothe end of the process by which supplementary services are provided bythe call agent 24 in connection with the MCF 22 for wireless calls.

FIGS. 11A–I illustrate supplementary service messages in accordance withone embodiment of the present invention. In this embodiment, themessages are SIP messages communicated to, from and/or between the MCF22 and the call agent 24.

Referring to FIG. 11A, SIP feature activation/de-activation messagesinclude a connection management (CM) server request message 320 and afeature request response message 322. The CM service message 320 isgenerated by the MCF 22 and communicated to the call agent 24 forprocessing. The feature request response message 322 is generated by thecall agent 24 and forwarded to the MCF 22 for processing. The featurerequest response message 322 includes a confirmation tone orannouncement SIP extension parameter.

Referring to FIG. 11B, SIP messages for abbreviated dialing include CMservice request message 324. The CM service request message 324 isgenerated by the MCF 22 and forwarded to the call agent 24 forprocessing.

Referring to FIG. 11C, SIP messages for calling number identificationpresentation/restriction (CNIP/CNIR) include a CM service requestmessage 326 and ISUP initial address message (IAM) message 328. The CMservice request message 326 is generated by the MCF 22 and forwarded tothe call agent 24 for processing. The ISUP IAM message 328 is generatedby the call agent 24 and forwarded to the MCF 22 for processing.

Referring to FIG. 11D, SIP messages for call forwarding unconditional(CFU) include infodir message 330 and flash with informationacknowledgment message 332. The infodir message 330 is generated by thecall agent 24 and forwarded to the MCF 22 for processing. The infodirmessage 330 includes treatment code SIP extension parameters. Aspreviously discussed, the treatment code parameters may comprise aconfirmation tone or announcement. Upon receipt of the infodir message330, the MCF 22 sends a flash with information to the mobile device 36with either the signal parameter or the information record causing themobile to apply abbreviated alert signal. Call agent 24 sends the resultof the alerting action to the HLR/VLR 86 and infodir. The call agent 24may perform CFU when CFU is activated for calls homed in the packetnetwork.

The flash with information acknowledgment message 332 is generated byMCF 22 in response to the infodir message 330 and forwarded to the callagent 24 for processing.

Referring to FIG. 11E, SIP messages for call forwarding no answer (CFNA)include page or answer timeout message 324. The page or timeout message324 is generated by the MCF 22 and forwarded to the call agent 24. Inone embodiment, the call agent 24 will perform CFNA when the MCF 22responds with the SIP response code of temporarily unavailable. If themobile device 36 is homed in the packet network, the call agent 24 willperform the call forwarding. If the mobile device 36 is not homed in thepacket network, the call agent 24 responds to the originating MSC with aredirect requirement with redirection parameters set to no answer or noresponse to paging.

Referring to FIG. 11F, SIP messages for call waiting include ISUP IAMmessage 336, initial flash with information message 338 and subsequentflash with information message 340. ISUP IAM message 336 is generated bythe call agent 24 and forwarded to the MCF 22 for processing. The flashwith information messages 338 and 340 are generated by the MCF 22 andforwarded to the call agent 24 for processing. The call agent 24 canreceive the incoming call from either PSDN or from the legacy MSC orfrom the packet network. In one embodiment, the call agent 24 determinesfrom the profile of the mobile device 36 that it has the call waitingfeature activated and determines from its state that the mobile device36 is busy. Because the incoming call is routed based on TLDN or themobile identification number (MIN) the call agent 24 has mapping of theTLDN to MIN number whenever a TLDN is allocated for the call. In thiscase, an invite request will be generated by the call agent 24 to theMCF 22 for the second call session. The call agent 24 will includeservice traffic position (STP) information about the bearer in theinvite request.

The MCF 22 will start a second call session for a call and send theflash with information message 338 to the mobile station 36 via the BSC32. If the mobile device 36 accepts the call, the flash with informationmessage 338 is sent to the MCF 22. The MCF 22 sends an answer messageand the first call is placed on hold. The MCF may use media gatewaycontrol protocol (MGCP) interface to toggle between the two call agentconnections. Subsequently, if the mobile device 36 switches from onecall to the other by sending a flash with information message, the MCF22 will place a current call on hold and switch to the original call.The MCF 22 notifies the call agent with SIP info request with flash totoggle between the call agents.

Referring to FIG. 11G, SIP messages for voicemail waiting notificationinclude qualification directive request message 342 and qualificationdirective response message 344. The qualification directive requestmessage 342 is generated by the call agent 24 and forwarded to the MCF22 for processing. The qualification directive response 344 is generatedby the MCF 24 in response to the request message 342 and forwarded tothe call agent 24 for processing. The qualification directive requestmessage 342 includes message wait notification count and message waitnotification type SIP extension parameters. Alternatively, subscribe andnotify methods may be used for message waiting notification.

Referring to FIG. 11H, SIP messages for voice mail retrieval includeservice request message 346 and location request response message 348.The service request message 346 is generated by the MCF 22 and forwardedto the call agent 24 for processing. The location request responsemessage 348 is generated by the call agent 24 in response to the requestmessage 346 and returned to the MCF 22 for processing.

Referring to FIG. 11I, SIP messages for calling name presentation andrestriction (CNAP and CNAR) include ISUP IAM message 350. ISUP IAMmessage 350 is generated by the call agent 24 and forwarded to the MCF22 for processing and includes calling party name SIP extensionparameters.

Other supplementary services may comprise location update messages andlocation specific services. In one embodiment, location specificinformation is passed in the invite message. This information may bedisplayed in the called party screen. For example, new services likelocation identification restriction (LIR) and location identificationpresentation (LIP) may be implemented. Location specific information maycomprise the serving cell site identifier or latitude longitude of thecell site with the FS 88 providing useful location information to mobileuser or other party. The location specific information or servicesduring a call may include alerts, advertisements, network congestioninformation and the like.

FIG. 12 illustrates call flow messages for caller location presentation(CLAP) and caller location restriction (CLAR) services in accordancewith one embodiment of the present invention. In this embodiment, themessages between the MCF 22 and the call agent 24 may be passed usingextended SIP.

Referring to FIG. 12, a first mobile device 370 initiates a servicerequest 372 which is passed to a first MCF 374 serving the first mobile370. The MCF 374 forwards location information for the mobile device 370to a location server 376. The location information may include callerID, MCF ID and BTS ID. The location server 376 returns locationcoordinate information 378 to the first MCF 374. The location coordinateinformation may include identification of a nearest intersection andother readily usable, useful and/or understandable location information.

The first MCF 374 generates an invite message 380 for the servicerequest, including the location coordinates 378. The invite message 380is passed to a call agent 382.

The call agent 382 forwards the invite message with the locationcoordinates to a second MCF 384 servicing a second mobile 386 of theconnection. The second MCF 384 determines whether CLAP is enabled forthe called party and whether CLAR is enabled for the caller. If CLAR isnot enabled for the calling party, the second MCF 384 will pass thelocation coordinates to the second mobile 386 if CLAP is enabled for thecalled party. If CLAR is enabled for the calling party, the second MCF384 will not pass the location coordinates to the second mobile 386.Paging and servicing setup messages 388 are also passed from a secondMCF 384 to the second mobile 386. Response and/or acknowledgmentmessages 390 may be passed back from the second MCF to the call agent382 and from the call agent 382 to the first MCF 374. The MCF 374 maythen pass a call party off hook message to the first mobile 370.

Although the present invention has been described with severalembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present invention encompasssuch changes and modifications as fall within the scope of the appendedclaims and their equivalents.

1. A method of control signaling for a wireless access network,comprising: receiving from a wireless access network a signaling messagefor a mobile device, the signaling message in a wireless-specificformat; converting the signaling message to a native format of a callagent to generate a call agent message, the call agent messagecomprising wireless-specific information of the signaling message; andcommunicating the call agent message to a call agent for processing,whereby the call agent support location updates for the mobile device inthe wireless access network, wherein the signaling message comprises alocation update message for the mobile device, and wherein the callagent message comprises a session initiation protocol (SIP) message, theSIP message comprising an extension including the wireless-specificinformation.
 2. The method claim 1, wherein the signaling messagecomprises a call establishment message for the mobile device.
 3. Themethod of claim 1, wherein the signaling message comprises a mobilitymanagement message for the mobile device.
 4. The method of claim 1,wherein the signaling message comprises a registration message for themobile device.
 5. A system of control signaling for a wireless accessnetwork, comprising: means for receiving from a wireless access networka signaling message for a mobile device, the signaling message in awireless-specific format; means for converting the signaling message toa native format of a call agent to generate a call agent message, thecall agent message comprising wireless-specific information of thesignaling message; and means for communicating the call agent message toa call agent for processing, whereby the call agent support locationupdates for the mobile device in the wireless access network, whereinthe signaling message comprises a location update message for the mobiledevice, and wherein the call agent message comprises a sessioninitiation protocol (SIP) message, the SIP message comprising anextension including the wireless-specific information.
 6. The systemclaim 5, wherein the signaling message comprises a call establishmentmessage for the mobile device.
 7. The system of claim 5, wherein thesignaling message comprises a mobility management message for the mobiledevice.
 8. The system of claim 5, wherein the signaling messagecomprises a registration message for the mobile device.
 9. A system ofcontrol signaling for a wireless access network, comprising: logicencoded in computer readable medium having instructions for execution ona processor: and to receive from a wireless access network a signalingmessage for a mobile device in a wireless-specific format: to convertthe signaling message to a native format of a call agent to generate acall agent message, the call agent message comprising wireless-specificinformation of the signaling message; and to communicate the call agentmessage to a call agent for processing, whereby the call agent supportlocation updates for the mobile device in the wireless access network,wherein the signaling message comprises a location update message forthe mobile device, and wherein the call agent message comprises asession initiation protocol (SIP) message, the SIP message comprising anextension including the wireless-specific information.
 10. The system ofclaim 9, wherein the signaling message comprises a call establishmentmessage for the mobile device.
 11. The system of claim 9, wherein thesignaling message comprises a mobility management message for the mobiledevice.
 12. The system of claim 9, wherein the signaling messagecomprises a registration message for the mobile device.
 13. A method forcontrol signaling for a wireless access network, comprising: receivingfrom a wireless access network a signaling message in awireless-specific format, the signaling message comprising locationinformation for a mobile device; converting the signaling message to asession initiation protocol (SIP) message, the SIP message comprisingthe location information for the mobile device in an extension; andcommunicating the SIP message to a call agent for processing, wherebythe call agent support location updates for the mobile device in thewireless access network, wherein the signaling message comprises alocation update message for the mobile device, and wherein the callagent message comprises a session initiation protocol (SIP) message, theSIP message comprising an extension including the wireless-specificinformation.